Tuesday, July 9, 2013

SID-Boy Cartridge Continuation

I could easily have written this post yesterday immediately after the last one because I was up working all night but so many components, arrangements, etc. changed. Now, I only minored in engineering at Central Michigan University but I plan on mastering in it eventually once my bills are caught up...anyhow, I decided to remove the RAM for the time being because it will make for an easier memory mapping. Both the SID and RAM are to be written to and there is no room for a battery backup, so whats the point of RAM at all? At least at this point in time.

Currently I have the SwinSID, ROM, MBC5 mapper chip, components and ICSP all placed. The TDA1543 DAC IC will remain through-hole because these chips are difficult to locate and the SMT version happens to be larger because of 8 unused pins! I have replaced the massive crystal with a tiny surface mounted one and will replace the resistors with SMT resistors as well. The PLCC socket will be removed because it is too large to fit inside of a gameboy but for the time being, I could only locate a 29f040/49f040 library file as through-hole.

Shortly, I will remove the logic chip that was never utilized and move the headphone jack to the other side because "if" the Audio-IN pin works as I hope it does, the traces would need to be on the other side.

If design goes as planned (for future versions) I will be able to support up to 64MegaBits of ROM! can you imagine a program that large!? However, RAM will probably be placed once I figure out how to add both the SID and RAM into the same 64Kbit addressing space. I may even decide to use a memory module that requires no battery backing, which would be a little more costly but less consuming of space.Hell, my program could easily be modified to support a YM2612 version if the project pans out. Just keep reading!

Also, if I manage to create a working prototype, I will be starting a kickstarter page for this project.